System of control



H. R. MEYER.

SYSTEM OF CONTROL.

APPLICATION FILED ocr. 17, 1918.

Patented Aug. 30, 1921.

I IINVENTOR jfizrzyflfzgez BY 2 7 ATTORNEY WITNESSES UNITED STATES' PALENT OFFICE.

HARRY R. MEYER, OE WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING CO'MPANY, A CORPORATION OF PENNSYLVANIA.

SYSTEM OF CONTROL.

Specification of Letters Patent.

Patented Aug; 30, 1921.

Application filed October 17, 1918. Serial No. 258,537.

To all whom it may concern:

Be it known that I, liiniiny It. MEYER, a citizen of the United States, and a resident of lVilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Systems of Control, of which the following is a specification.

My invention relates to systems of control for electric motors and particularly to that type of railway system which is adapted for operation from two materially different supply-circuit voltages.

The object of my invention is to provide a system of the above-indicated character which shall effectively obviate certain op erating diiiiculties that have been experienced in the prior art in systems of the class under consideration.

More specifically stated, it is the object of my invention to provide a novel type of relay device, commonly known as an overload trip, which will function to fully protect the system irrespective of the particular supply-circuitvoltage that is being utilized and which is so interlocked with the control system proper that false operation of the high-voltage element of the relay device, when the system is operating from a supply circuit of relatively low voltage, is effectively and reliably precluded.

My invention may best be understood by reference to the accompanying drawings, wherein Figure 1 is a diagrammatic view of the main circuits and of the auxiliary governing circuits of a system of control embodying the present invention; and Fig. 2 isa detail diagrammatic view of one of the unit switches that is preferably employed in carrying out my invention. I

Referring to Fig. 1 of the drawing, the main circuits illustrated comprise suitable supply-circuit conductors respectively marked High-voltage trolley, Low-voltage trolley and Ground, the two trolleys being connected by a suitable section insulator; a plurality of electric motors respectively having armatures A1, A2, A3 and A4 and series-type field windings F1, F2, F3 and F4; a plurality of accelerating resistors 18 to 21, inclusive; and means for suitably governing the normal operation of the motors including line switches LS1 to LS4, inclusive resistor shortcircuiting switches R1, R2 and B3, series and parallelcircuit-arranging switches S1 and S8, and P and G,1espcctively, and a plurality of sections CO1, (10-2 and CO3 of a change-over switch, for respectively adjusting the circuits of the accelerating resistors and the pairs of motors having the armatures A1 and A2, and A3 and A l.

The several main-circuit switches are preferably of a familiar electrically-controlled type that is more fully shown in Fig. 2, and certain of these switches embody auxiliary or interlock contact members for governing auxiliary-circuit connections-to be described, in accordance with a well-known practice.

The change-over switch is preferably of a familiar drum type having two operative positions respectively corresponding to highvoltage and low-voltage operation, and designated as 5000 and 600, respectively, reference being had to the supply-circuit voltages. It will be appreciated that the in vention is not, however, limited to these particular voltages, but is applicable to any systems having materially different voltages. The changeover switch may be manually or otherwise operated, as will be understood, the particular type of operation being immaterial to the present invention.

The auxiliary control system comprises the various actuating coils and interlock contact members of the main-circuit switches, together with a master controller MC having a plurality of operative positions a to h, inclusive, for governing the energization of the various switch-actuating coils from a storage battery B or other suitable source of energy; and a plurality of contact members of a double relay device or tandem overload trip, the respective elements of which are designated as HV and LV, corresponding to high voltage and low voltage, respec tively, the actuating coils for the two relay elements being connected in series relation with the main motor circuit.

The two elements of the tandem overload trip have their actuating coils connected permanently in series, so that the total motor current flows through both coils under all operating conditions. Since the setting or adjustment of the high-voltage'trip HV is necessarily much lower than that of the low-voltage device LV, it will be seen that, when the system is operating from the 600- volt or other low-voltage supply circuit, the

high-voltage trip will normally be traversed by a relatively heavy current which would cause the device to operate and thus open the control circuits. Such action would, of course, prevent normal and satisfactory operation of the control system and, consequently, I have so interlocked the high -voltage element HV with the mainc1rcu1t switch LS2, which is employed only during low=voltage operation, that even though the high-voltage trip does operate during this period, no change is effected in the con trol system, which depends, for its overload protection, solely upon the other or low-voltage element LV, as about to be described in detail. 1

Assuming that it is desired to effect operation of the illustrated system from the high-voltage trolley, the master controller MG may be moved to' its first operating position a, whereupon a circuit is established from one terminal of the battery B through conductor 1, control fingers 2 and 3, which are bridged by the master controller con-- tact segment 4:, conductor 5, the parallelrelated actuating coils of the switches LS1, LS8 and LS, and conductors 6 and 7 to the opposite terminal of the battery B.

Another circuit is simultaneously established from the contact segment 1 through control finger 8, conductor 9, cooperating contact members 10 and 11 01" the higlrvolt age and low-voltage trips I -IV and LV, respectively,.in their lower or normal position, conductor 12, interlock P-out, the parallel-related actuating coils of the switches S1 and S2 and the interlock G-out, to the negative conductor 7.

Referring temporarily to the main circuits, the closure of the switches just mentioncd completes the main circuit from the trolley. through conductor 15, the actuating coils of both the high-voltage and low-voltage elements of the overload trip device, conductor 16, switches LS1, LS3 and LS I, conductor 17, accelerating resistors 18 to 21, in elusive, which are connected in series relation during'the high-voltage operation of the system, as indicated by the position of the change-over switch section CO1, circuit being continued from the resistor 21 through conductors 22 and 23, armature A1, field windings Fl, conductor 24, contact segment of the change-over switch section (JO-2 in its high-voltage position, conductor 26, armature A2, field winding F2, conductor 27, switches S1 and S2, conductor 28 armature A3; field winding 3, conductor 29, contact segment 30 of the changeover switch section (JO-23 in its higlrvoltage position, conductor 81, armature A l, field winding F 4; and conductor 32 to the negative supply-circuit conductor Ground. ii

.If the master controller is successively moved to positions 6, 0 and d, control fingers 33, 3e and 35 are respectively engaged by the contact segment 4; to energize the coils of the switches R1, R2 and R3, thus successively short-circuiting the several accelerating resistors. It will be understood that the num her and arrangement of the accelerating resistors will be varied to suit operating re quirements and that the present arrangement is merely for illustrative purposes.

Upon movement of the master controller vlC to its initial parallel position a, the control fingers 33, and 35 first become dis engaged from the contact segment 1 to again insert the accelerating resistors in circuit temporarily, and then a new circuit is es tablished through control. linger 36, conductor 3664, contact members 37 and 38 of the high-voltage and low-voltage elements, respectively, of the overload trip, conductor 39 and the actuating coil of the switch G to the negative conductor 7.

The control linger 8 next breaks contact with the segment l to decnergize the actuat ng coils of the switches S1 and S2 and cause the opening of the previously-traccd series circuit at the corresponding point, However, as soon as the switch S2 drops out, a new circuit is completed from the positively-energized conductor 39 through intcrlock S2-out and the actuating coil of the switch P to the negative conductor 7. The purpose of the interlocks SQ-out, Pl-out and G-out is to prevent any possibility of a simultaneous closure of these three switches, which would create a short circuit, as will be understood.

T he closure of the switches P and Gr and the concurrent opening of the switches S1 nd S2 -forms new circuits, one of which is continued from the accelerating resistor 21 through conductors 22 and 23, armature A1, field winding Fl, armature A2 and field winding F 2, as previously traced, to the conductor 27, whence circuit is completed through conductor 4-5, switch Gr and conductor 46 to the negative supply-circuit conductor Ground. A branch circuit is continued from the conductor 22, through conductor 4:7, switch P, conductors -18 and 28 and the motors having the armatures A3 and as previously traced, to Ground.

By operating the master controller to its successive positions f, g and FL, the resistor short-circuiting switches R1, R2 and R3 are again closed to gradually efi'ect further acceleration of the motors.

It, for any reason, unduly high current conditions occur in the main motor circuit, corresponding to the setting of the highvoltage element of the overload trip, this element will be actuated to its upper or open-circuit posit-ion to open either the pairs of switches S1 and S2, or P and G, and thus automatically prevent further motor 0 eration under such injurious conditions. 0W-

its

ever, if preferred, the overoad trip may readily be adapted to open the line switches, either alone or in conjunction with those illustrated. Although no locking device is shown in the drawing, it will be understood that one of the well-known types of locking devices for holding the overload trip in its open position whenever. it operates, should preferably be provided, so that the motorman is obliged to return the master controller to the off position and manually reset the overload trip before the system may again be operated.

It will be appreciated that, under conditions of operation from the high-voltage supply circuit, the relatively light current traversing the coil of the low-voltage element LV ofthe overload trip is insufficient to actuate it to its open-circuit position and, consequently, the overload protection for the system is furnished solely by the high-voltage element HV. I

Assumin now that the railway vehicle under"consideration is to be operated from the low-voltage supply circuit by reason of passing through a town or athickly-populated district, the change-over switch is first thrown to its lowvoltage position marked 600. Such actuation of the change-over witch causes the section GO.1 to connect the resistors 18 and20' in parallel relation with the resistors 19 and 21, such connection of the-resistors being desirable in view of the lower voltage that is impressed upon the main motor circuits. Furthermore, the change-over sections CO2' and (10- 3 serve to connect the corresponding pairs of motors in. parallel relation so that, in lieu of the previously-traced circuit through the motors having 'armatures A1 and A2, the following circuits obtain: from the accelerating resistors through conductor 22 to va contact member 52, where the circuit divides, one branch 'incliiding conductor 23,. armature A1, field winding Fl, conductor 24 and contact segment 53, and the other branch traversing conductor 26, armature A2, field winding F2, conductor 27 and the contact segment 53, whence a common circuit is continued through switches S1 and S2, whenever the master controller occupies any one of its series positions. A similar rearrangement of circuits occurs inconnection with the remaining pair of motors.

The only change caused in the auxiliary circuits by the operation of the change-over switch to its low voltage position is the inclusion in the circuit of the actuating coil for the switch LS2 of a contact member 49, whereby this actuating coil is connected in parallel relation with those of the other line switches. The purpose of this arrangement is as follows. Although the switches LS3 and LS4 are designed to carry the much heavier current that flows through the main circuit upon the parallel connection of the pairs of motors during low-voltage operation, the switch LS1 is not so designed, but is primarily adapted for breaking the highvoltage circuit and is of insufficient current capacity to withstand the full current corresponding to low-voltage motor operation. Consequently, the switch LS2 is connected in parallel relation to the switch LS1 under low-voltage operating conditions, whereby the high-voltage line switch LS1 carries a current no greater than that traversing it during high-voltage operation.

If the master controller is now moved to its initial operating position a, the line switchesLSl, LS3 and LS4 and the series switches S1 and S2 are again closed in the manner previously set forth and, in addition, the switch LS2 is closed by reason of the use of the above-mentioned changeover switch contact segment 49. As soon as the line switch LS2 has closed, interlock contact segments 50 and 51 thereof respectively bridge the contact members 37 and 10 of the high-voltage element HV of the overload trip. Consequently, even though the highvoltage element, by reason of the heavy current traversing its actuating coil, is actuated to its open-circuit position, no effect is pro duced upon the control circuits by reason of the use of the interlock contact members 50 and 51, which thus insure the maintenance of the circuit for the actuating coils of the pairs of switches P and G, and S1 and S2, respectively. In this way, the overload or high-current protection for the system when operating from the low-voltage supply circu'it, is provided entirely by the low-voltage element LV of the overload trip device.

The remainder of the operation of the control system is identical with that already set forth, and no further explanation thereof is believed to be necessary. I

.As previously stated, the operation of either element of the tandem overload trip will preferably maintain the open-circuit condition of the auxiliary system by means of familiar locking device until the master controller is returned to its off position. and the overload trip is manually reset. In the system that is illustrated, it would be necessary to manually reset the trip devices whenever the change-over fromv low voltage to high-voltage operation was made, by reason of the above-mentioned actuation of the high-voltage element HV to its open circuit position during low-voltage operation of the motor. However, this difficulty may readily be obviated by providing a contact segment in the intermediate ofi position of the change-over switch, whereby the high-voltage element may be reset electrically in accordance with a familiar practice, and the train operator need pay no further attention thereto.

I do not Wish to be restricted to the specific circuit connections or arrangement of parts herein set forth, as various modifications thereoi may be made without departing from the spirit and scope of my invention. I desire, therefore, that only such limitations shall be imposed as are indicated in the appended claims.

I claim as my invention:

1. In a system of control, the combination with a plurality of supply circuits of materially different voltages and a dynamoelectric machine, of means for preventing predetermined abnormal operating conditions in said machine during operation from any one of said supply circuits, and means operative only during one type of system operation for preventing effective action of a portion of the first-mentioned means.

2. I11 a system of control, the combination with two supply circuits of materially different voltages and a dynamo-electric machine, of means for preventing predetermined abnormal operating conditions in said machine during operation from either of the supply circuits, and interlocking means operative only during operation of the system from the lower-voltage supply circuit for preventing effective action of a portion of the first-mentioned means corresponding to the higher-voltage supply circuit.

In a system of control, the combination with two supply circuits of materially dif- -ferent voltages and a dynamo-electric machine, of relay means having portions operatively corresponding to the respective supply circuits for preventing predetermined abnormal operating conditions in said machine during operation from either of the supply circuits, and interlocking means 0perative only during operation of the system from a certain one of said supply circuits for preventing effective action of the portion of said relay means corresponding to the other supply circuit.

4. In a system of control, the combination with two supply circuits of materially different voltages and a dynamo-electric machine, of double relay means having series-connected coils operatively corresponding to the respective supply circuits and energized in accordance with a predetermined machine condition, and interlocking means operative only during operation of the system from the lower-voltage supply circuit for preventing effective action of the portion of said relay means corresponding to the higher-voltage supply circuit.

5. In a system of control, the combination with two supply circuits of materially different voltages and a dynamo-electric machine, of two relay devices having their series-connected coils energized from the machine circuit and operatively corresponding to the respective supply circuits, a switching device employed only during operation of the system from the lower-voltage circuit, and contact means actuated by said switching device for rendering the action of the relay device corresponding to the higher-voltage supply circuit ineffective.

6. In a system of control, the combination with two supply circuits of materially different voltages and a dynamo-electric machine, of two relay devices operatively corresponding to the respective supply circuits having their series-connected coils energized in accordance with the machine current, the contact members of the relay devices serving to effect the opening or closure of the machine circuits, a switch employed only during operation of the system from the 1ower-voltage circuit, and contact means actuated by said switch for bridging the contact members of the relay device corresponding to the higher-voltage supply circuit.

7 In a system of control, the combination with a plurality of supply circuits of materially different voltages and a dynamoelectric machine, of protective relay means for said machine interlocked to permit effective action of only one of its portions during operation of the machine from one of said supply circuits.

8. The combination with a plurality of supply circuits of different characters and a dynamo-electric machine, of protective means for said machine governed by the operation thereof from one supply circuit for permitting effective action of only one portion of said protective means.

In testimony whereof, I have hereunto subscribed my name this 25th day of Sept,

HARRY n. MEYER. 

